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Full text of "The Cambridge Natural History"

198

SERIAL AND INTERLOCKING CARPUS

Matthew.1 He has pointed out that in some ancient Ungulates
the carpus is not serial but interlocking, even in forms which
belong to the earliest Eocene groups, such as the genus Protolambda
among the Amblypoda. N"ow in the fore-foot of JMTenisGotJierium
and the living Syrax there is a separate centrale which is wanting
in the greater number of Ungulates. The absorption, that is the
practical dropping out of this bone, would restore to an interlocking
carpus the serial arrangement ; while on the other hand, by the

FIG. 112.  Bones of the mamiy A, of the Indian Elephant, JSlephas indicus. x .
B, of the Cape Hyrax, Jffyraoc capeTtsis. x 1. <?, Cuneiform ; cc, centrale ; lt
lunar ; in, magnum ; p, pisiform ; Mf radius ; td, trapezoid j ?,, trapezium ; $,
scaphoid; *, unciform ; U, ulna. (From Flower's Osteology.)

fusion of this bone with the scaphoid, the interlocking disposition
would be maintained.

The gradual perfecting of the fore- and hind-limbs as running
organs has been put down to the advent of the grasses, and the
formation of large plains covered with this herbage. The same
reason would also be in harmony with the equally gradual change
in the shape o the molar teeth,, from a tubercular form calculated
for a mixed or even a carnivorous diet, to the flatter crushing stir-
faces exhibited by the lophodont teeth of later Ungulates. Strong

EulL

r. Mtts, N~at. Hist. ix. 1897, p. 321.